[SOLVED] => LINQ query IEnumerable<Object> for IEnumerable<DataRow>...

Question

Why is my LINQ query ("rows") showing up as a null when it seems like I have plenty of data ("waypoints")?

I'm doing an insert of ~20k records and rather than go through Entity Framework I've opted for SqlBulkCopy, which seems to mean I need a datatable. I'm trying to get an IEnumerable into IEnumberable as that seems to be the only way to get CopyToDataTable().

I was copying the syntax in this answer, and you can see in my debugger that I have plenty of objects in my original list but IEnumerable is null.

enter image description here

Same code, maybe easier to read:

    IEnumerable<DataRow> rows =
            (from w in waypoints.AsEnumerable()
            select w)  as IEnumerable<DataRow>;

    DataTable table = rows.CopyToDataTable();

The "rows" variable is returning as null.

Eric

Accepted Answer

You are trying to typecase an IEnumerable<Waypoint> as an IEnumerable<DataRow>, which is not going to work unless your Waypoint class is derived from DataRow, which I assume it's not. The documentation for the CopyToDataTable method is pretty clear:

The parameter T of the input parameter source can only be of type DataRow or a type derived from DataRow.

You are going to have to make your data table the long way, unfortunately. Make a new blank DataTable, add columns to it's Columns collection, then add rows to it's Rows collection.

Michael Edenfield

LINQ query IEnumerable

Question

Fastest Entity Framework Extensions

Accepted Answer

Performance

Expression Evaluator